Used primarily in microbiology for the selective isolation and differentiation of Salmonella species from other enteric bacteria. The medium supports the growth of Salmonella while inhibiting Gram-positive bacteria and many non-Salmonella Gram-negative organisms due to the presence of sulfite and bismuth compounds. Salmonella colonies typically appear as black centers due to hydrogen sulfide production, which reacts with bismuth to form black bismuth sulfide. Commonly used in food, water, and clinical testing to detect Salmonella contamination.